Synthesis of 5-[(Thiophen-3-yl)amino]-1,2,4-triazines

Russian Journal of Organic Chemistry - Methyl 3-(3,6-diaryl-1,2,4-triazin-5-ylamino)thiophen-2-carboxylates were synthesized in 70–75% yield by solvent-free reaction of methyl...     

Synthesis and structure of 4-[(4-Nitro-1,2,5-oxadiazol-3-yl)-NNO-azoxyl]-1, 2,5-oxadiazol-3-amine

The synthesis of the energetic compound 4-[(4-nitro-1,2,5-oxadiazol-3-yl)-NNO-azoxyl]-1,2,5-oxadiazol-3-amine (3) was achieved in two steps from diaminofurazan (1). Compound 3 was characterized by X-ray diffraction. From the X-ray structure a bifurcated intramolecular H bond between O(2)-H(2)-N(4) was observed. In addition, intramolecular H bonding was observed between H(1) and N(7) of an adjacent molecule. One molecule of ethanol and one-half molecule of water per molecule of3 was observed in the crystal lattice. However, no H bonding was observed between the solvent molecules and3 in the crystal lattice. Despite the presence of solvent in the crystal lattice,3 was found to have a high crystal density (d=1.856 g/cm³).     

Microwave-induced one-pot synthesis of 4-[3-(aryl)-1,2,4-oxadiazol-5-yl]-butan-2-ones under solvent free conditions

The synthesis of 4-[3-(aryl)-1,2,4-oxadiazol-5-yl]-butan-2-ones (5a-l) from methyl levulinate (4) and arylamidoximes (1a-l) is described. The reaction was carried out in a microwave oven without any solvent in much shorter time and in yields comparable with conventional heating.     

Aroylnitrile oxide cyclizations. 1. Synthesis of (3-aroyl-1,2,4-oxadiazol-5-yl)acetic acids

Intrermolecular cyclization of 1,3-dipolar aroylnitrile oxides to malononitrile provided a viable approach to a variety of novel (3-aroyl-1,2,4-oxadiazol-5-yl)acetic acid derivatives.     

Synthesis of 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)-ethyl]benzimidazole and its x-ray analysis

Cyclization of O-benzoyl-2-(benzimidazol-1-yl)propioamidoxime under different temperature conditions gave 2-[2-(5-phenyl-1,2,4-oxadiazol-3-yl)ethyl]benzimidazole whose structure has been determined by X-ray analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1057–1061, July, 2006.     

Synthesis and structures of 4,6-disubstituted 2-(5-methyl-1,2,4-oxadiazol-3-yl)-1,3,5-triazines

New 1,2,4-oxadiazolyl-1,3,5-triazines were synthesized from amidoximes derived from sym-triazine mononitriles. The structure of one of the resulting compounds was studied in detail by X-ray diffraction. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1845–1850, August, 2005.     

Design,Synthesis, and Anticancer Evaluation of 2-{3-{4-[(5-Aryl-1,2,4-oxadiazol-3-yl)methoxy]phenyl}isoxazol-5-yl}-N-(3,4,5-trimethylphenyl)thiazol-4-amine Derivatives

Russian Journal of General Chemistry - A series of new 2-{3-{4-[(5-aryl-1,2,4-oxadiazol-3-yl)methoxy]phenyl}isoxazol-5-yl}-N-(3,4,5-tri-methylphenyl)thiazol-4-amine derivatives is synthesized, and...     

3-Aryl-5-[(aryloxy)methyl]-3-[(1H-1,2,4-triazol-1-yl)methyl]-2-methylisoxazolidine derivatives. Synthesis and antifungal activity

The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)methyl]-3-[(1H-1,2,4-triazol-1-yl)-methyl]-2-methylisoxazolidines are described. The in vitro activity was evaluated in solid agar cultures against a variety of dermatophytes and yeast fungi, while in vivo activity was measured in an immune-compromised mouse model of systemic candidiasis. The activity of the title series was compared to that of ketoconazole and one derivative, the cis-3-(4-chlorophenyl)-5-(4-chlorophenyloxy)methyl analogue 5f was found to possess a similar potency in the in vivo assay. Structure-activity relationship correlations are also discussed.     

Synthesis of 3-(5-Aryl-1,3,4-oxadiazol-2-yl)chromones

A general method was proposed for the synthesis of 3-(5-aryl-1,3,4-oxadiazol-2-yl)chromones starting from 3-formylchromone. This aldehyde yields acylhydrazones, from which the corresponding unstable nitrile imines are generated. These intermediates undergo intramolecular 1,3-dipolar cycloaddition.     

Synthesis of 3-(5-Aryl-1,3,4-oxadiazol-2-yl)chromones

A general procedure was proposed for the synthesis of 3-(5-aryl-1,3,4-oxadiazol-2-yl)chromones by reaction of 3-formylchromone with aroylhydrazines, transformation of the corresponding acylhydrazones into 1,3-dipoles by the action of bromine in the presence of sodium acetate, and intramolecular ring closure.     

苯甲酸（1H－1，2，4－三唑－1－基）－3，3－二甲基－2－丁酮酯衍生物的合成

用冠醚作催化剂，通过苯甲酸盐同１－溴代－１－（１Ｈ－１，２，４－三唑－１－基）－３．３－二甲基丁酮－２－反应，合成了一系列苯甲酸（１Ｈ－１，２，４－三唑－１－基）－３，３－二甲基－２－丁酮酯类新化合物，并对合成方法进行了探讨。通过ＩＲ、￣１ＨＮＭＲ及元素分析，确定了化合物的结构。     

Synthesis of 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles

5-(2,5-Dimethylphenyl)-1,2-oxazole-3-carbaldehyde oxime reacted with acetic anhydride in pyridine to give 5-(2,5-dimethylphenyl)-1,2-oxazole-3-carbonitrile which was converted into the corresponding amide oxime by treatment with hydroxylamine. O-Acyl derivatives of N′-hydroxy-5-(2,5-dimethylphenyl)-1,2-oxazole-3-carboximidamide underwent heterocyclization into 5-substituted 3-[5-(2,5-dimethylphenyl)-1,2-oxazol-3-yl]-1,2,4-oxadiazoles on heating in acetic acid.     

Synthesis and anticonvulsant activity of 3-[3-[(dimethylamino)-methyl]-5-methyl-4H-1,2,4-triazol-4-yl]-4-(o-chlorobenzoyl)pyridine

Wolff-Kishner reduction of 3-amino-4-(o-chlorobenzoyl)pyridine ( 3 ) afforded 3-amino-4-(o-chlorobenzyl)pyridine ( 5 ), which on subsequent reaction with triethyl orthoformate and then acetyl hydrazide yielded 1-acetyl-2-[N-[4-(o-chlorobenzyl)pyridin-3-yl]formimidoyl]hydrazone ( 7 ). Cyclization of hydrazone 7 gave 3-(3-methyl-4H-1,2,4-triazol-4-yl)-4-(o-chlorobenzyl)pyridine ( 8 ), which on Jones oxidation yielded 3-(3-methyl-4H-1,2,4-triazol-4-yl)-4-(o-chlorobenzyl)pyridine ( 9 ). The Mannick reaction of 3-(3-methyl-4H-l,2,4-triazol-4-yl)-4-(o-chlorobenzyl)pyridine ( 9 ) with aqueous formalin and dimethylamine hydrochloride afforded 3-[3-[(dimethylamino)methyl]-5-methyl-4H-1,2,4-triazol-4-yl]-4-(o-chlorobenzoyl)-pyridine ( 10 ). 3-[3-[(Dimethylamino)methyl]-5-methyl-4H-1,2,4-triazol-4-yl]-4-(o-chlorobenzoyl)pyridine ( 10 ) exhibited good anticonvulsant activity in the subcutaneous pentylenetetrazole anticonvulsant screen indi cating that an appropriately substituted-pyridine ring moiety can serve as a bioisostere of a chlorobenzene ring with respect to anticonvulsant activity.     

Carbon-13 NMR Studies of 3-Aryl-4-(5-aryl-Δ 2-1,2,4-oxadiazolin-3-yl)sydnones and 3-Aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones

The ¹³C NMR spectra of twelve 3-aryl-4-(5-aryl-Δ²-l,2,4-oxadiazolin-3-yl)sydnones and twelve 3-aryl-4-(5-aryl-l,2,4-oxadiazol-3-yl)sydnones have been measured and assigned by means of proton-noise decoupling and DEPT-experiments. The coupling constants were determined by means of gated decoupling, and NOE effects were observed by comparison of proton-decoupled and inverse-gated decoupled spectra. Differences shown by the oxadiazoline and the oxadiazole rings and the substitution effects are discussed.     

Synthesis of N-methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine

N-Methyl-N-[(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl]amine (1)(1) is a key intermediate in the preparation of premafloxacin (2), which was under development as an antibiotic for use against pathogens of veterinary importance. This paper describes the development of a practical, efficient, and stereoselective process for the preparation of 1 from isobutyl (3S)-3-[methyl[(1S)-1-phenylethyl]amino]butanoate (5c). The key steps in the synthetic sequence are an asymmetric Michael addition, which yields 5c, and a stereoselective alkylation, which yields (3S,4S)-3-allyl-1,4-dimethylazetidin-2-one (17).     

A handy and solventless direct route to primary 3-[3-aryl)-1,2,4-oxadiazol-5-yl]propionamides using microwave irradiation

A one-step, simple and straightforward synthesis of the title amides from the corresponding carboxylic acids, urea and imidazole under microwave irradiation is described.     

Synthesis and structure of hydrazones obtained from hydrazides of [5-(4-pyridyl)-1,3,4-oxadiazol-2-ylthio]acetic or 2-[5-(4-pyridyl)-1,3,4-oxadiazol-2-ylthio]propionic acids

It has been shown by¹H NMR spectroscopy that hydrazones obtained by the condensation of hydrazides of [5-4-pyridyl)-1,3,4-oxadiazol-2-ylthio] acetic or 2-[5-(2-pyridyl)-1,3,4-oxadiazol-2-ylthio]propionic acids with aldehydes, ketones, and -dicarbonyl compounds exist in DMSO solution as a mixture of stereoisomeric forms.Institute of Chemistry, Vilnius LT-2600, Lithuania. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 966–971, July, 2000.